Apparatus for extruding cable jackets with embedded drain wires

ABSTRACT

Apparatus for extruding a cable jacket with embedded drain wires comprises a die with radial recesses into which are fitted hardened guide blocks with passages for the wires.

1111B States P319111 1191 Arnaudin, Jr.

1 1 Jan. 23, 1973 [54] APPARATUS FOR EXTRUDING CABLE JACKETS WITHEMBEDDED DRAIN WIRES [75] Inventor: Edwin H. Arnaudin, Jr., New York,

[73] Assignee: Anaconda Wire and Cable Company 22 Filed: June 18,1971

52 U.S.C1. ..425/114,156/l43,156/500, 264/173, 264/174 [58] Field ofSearch ..425/114, 461; 156/51, 143, 156/244, 500; 72/17; 264/173, 174

[56] References Cited 7 UNITED STATES PATENTS 3,252,183 5/1966 Bronzert..425/114 10/1970 M'h'aif flIjluu 3,534,437 10/1970 Quackenbush..3,582,417 6/1971 Plate et al ..l56/51 Primary Examiner-J. SpencerOverholser Assistant Examiner-Brian P. Ross Attorney-Victor F. VolkABSTRACT Apparatus for extruding a cable jacket with embedded drainwires comprises a die with radial recesses into which are fittedhardened guide blocks with passages for the wires.

5 Claims, 5 Drawing Figures PATENTEBJAN 2 3 ms 3 t 7 12,7 7 0 sum 1 OF 2Fig. 3 EDWIN H. ARNAUDIN PATENTEDJANZSIQYS 3,712,770

SHEET 2 or 2 F g 4 INVENTOR.

EDWIN H. ARNAUDIN APPARATUS FOR EXTRUDING CABLE JACKETS WITH EMBEDDEDDRAIN WIRES BACKGROUND OF THE INVENTION This invention is directedtoward apparatus for making electric cables such as those described inUS. Pat. Nos. 3,473,189, 3,571,613 and 3,582,417 wherein drain wires areembedded in the cable jacket. In [1.8. Pat. No. 3,531,962 apparatus isdescribed for paying the drain wires through a slotted guider tube in anextruder head. I have found, however, that apparatus paying the wiresthrough an extruder guider tube is troublesome in that the jacketmaterial being extruded may block a slot in the guider tube if there isa break in one of the wires. Because of the inaccessability of theplugged area of the slot it is then necessary to shut down the extrusionmachine, unplug the slot, and

rethread another wire through it before production of cable cancontinue.

SUMMARY guide blocks fit into these recesses. The guide blocks comprisewalls that define passages for the drain wires with the walls of theblocks projecting'radially inwardly of the die land. The bocks are madeof material that is harder and more wear resistant than the material ofother portions of the die. Preferably my apparatus comprises taperedgrooves in the interior surface immediately adjacent to the blocks toincrease the flow of jacket material over the drain wires duringextrusion, and the blocks are fixed in position by means of cooperatinglengthwise grooves in both the recess walls and the blocks.Advantageously my die may comprise three separable sections with theland in the first section, the recesses in the second, and slots in thethird section which communicate with the passages in the blocks to admitthe wires. A tubular housing in which the die is mounted may alsocomprise walls defining slots that communicate with the slots in thethird section of the die.

A more thorough understanding of my invention can be gained from a studyof the appended drawings:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a lengthwise section ofthe apparatus of my invention.

FIG. 2 shows a partial front view of the apparatus of FIG. 1.

FIG. 3 shows a lengthwise bottom view of the apparatus of FIG. 1.

FIG. 4 shows a pictorial side view of my removable guideblock.

FIG. 5 shows a section through the lines 55 of FIG. 4.

DETAILED DESCRIPTION OF A PREFERRED I EMBODIMENT Referring first to FIG.1 my apparatus indicated generally by the numeral 10 comprises anextruder cross head bolted to an extruder barrel 11 of conventionalconstruction from which it receives jacket material 12 being urgedoutward by a screw, not shown. The apparatus 10 comprises a tubularhousing 13 of substantial wall thickness so that it can withstand highinternal pressure of the material 12, a flanged spacer and flow diverter14 is bolted to the housing 13 and a core tube 16 is bolted, in turn tothe spacer 14. A tapered guider 17 threads onto the core tube 16. A die18 with a flange 19 is bolted against the housing 13 by means ofaretaining ring 21 and bolts 22. The die 18 is formed of three annularmembers bolted together by bolts 23. The first of these members 24 hasthe least thickness and comprises the land 26 of the die 19. A second ofthese members 27 comprises an interior tapered surface 28 communicatingwith a tapered surface 30 in the member 24 that terminates at the land26. A third member 29 has the greatest thickness or length and includesthe flange l9 and a cylindrical portion 31 with a projection 32 forequalizing material flow. The member 19 has an interior tapered surface33 continuous of the surface 28.

The housing 13 and die 18 together combine with the core tube 16 andguider 17 to define an annular channel 34 for the material 12 which isextruded finally as a jacket 36 over a cable core, not shown, with outerdimensions determined by the land 26. Six undulatory drain wires 37 arepaid over plastic guide sheaves 38 from a supply not shown to beembedded in the jacket 36.

For this purpose six guide blocks 39 (FIGS. 4 and 5) are inserted in alike member of radial recesses 41 in the member 27. The blocks 39 aremachined from highly abrasion resistant material such as tungstencarbide or steel reinforced with carbide particles such as Ferro-Tic C,available from the Sintercast Division of West Nyack, N.Y.

Interior walls 42 (FIG. 5) of the block 39 define a passage 43 in thenature of a slot with rounded edges for guiding the undulatory wires 37into the jacket being extruded. For this purpose it is necessary thatopenings 44 in the blocks should project radially inwardly beyond theland 26. To establish the proper position of the blocks 39 lengthwisegrooves 46 are cut in one wall. Grooves 47 are also cut in the walls ofthe recesses 41. The blocks can then be firmly fixed in proper positionsby inserting split hollow pins 48 into the bore formed by thecooperating grooves.

The inwardly projecting face of the blocks 39 are long enough to provideflat portions 49 over which the wires 37 are bent and caused to lieparallel to the axis of the cable.

Since the blocks 39 project into the flow of material through thechannel 34 I have found it advantageous to compensate for theinterruption to assure that a fully continuous layer of the material 12is deposited over and around the wires 37. For this purpose my die 18has tapered grooves 51, 52 formed in the surfaces 28, 30 of the of themembers 29, 27. As an example of the depth I have found satisfactory forthe grooves 51, 52,

where the width of a block 39 is about 0.218 inch the depth of thegrooves 51, 52 will taper from zero at upstream end of the member 27 toabout 0.0237 inch wide at the downstream end of the member 27. Thegrooves 51, 52 are conveniently made with a inch cylindrical cuttingtool mounted at an 8 angle to the axis of the member 27. Sphericalreliefs 53 in the member 24 are continuous with the grooves in themember 27 On leaving a sheave 38 a wire 37 follows a straight path untilit bends at the surface 49. So that this can occur the member 29 hasradial slots 54 which communicate with the passages 43 and the housing13 has radial slots 56 that communicate with the slots 54. Conveniently,to obtain the proper angle of entrance of the wires 37 into my apparatusI have mounted the sheaves 38 on supports 57 bolted directly into thehousing 13. From FIG. 1 it can be seen that the wires 38 enter thejacket 36 at a section downstream of the guider 17. Surprisingly thereis no tendency of the jacket material 12 to plug up the passages 43 evenif the wires 38 are interrupted. To introduce a new wire after one hasbroken the extrusion need not be stopped but the wire can be manuallyinserted through the passage 43, which has a flared opening 58 when itwill be seized by the advancing jacket material. In the operation of myapparatus the member 27 is first assembled with the blocks 39 beingfixed by the pins 48. The members 29, 27, and 24 are then assembled andlocked together by means of the bolts 23. The assembled die 18 is fittedinto the extruder head by means of the retaining ring 21. The wires 37are all threaded over their respective sheaves 38 through the slots 56and 54 through the passages 43 and tied around the core of a cable to bejacketed. This can be done with straight wire, that is without operatingthe corrugator which applies the wire undulations. After the extruder isoperating and jacket material is being affixed the corrugator isactivated and undulatory wire continues to pay through the passages 43.My apparatus is particularly adopted to the embedment of undulatorywires inasmuch as it does not tend to stretch out or change the pitch ofthe undulations.

The foregoing description has been exemplary rather than definitive ofmy invention for which I desire an award of Letters Patent as defined inthe following claims.

I claim:

1. Apparatus for extruding a cable jacket with embedded drain wirescomprising a die comprising:

A. a tapered, interior surface,

B. a cylindrical land communicating with said surface,

C. a plurality of radial recesses opening on said surface, and

D. a like plurality of removable guide blocks fitting into saidrecesses, said blocks comprising walls defining passages for said wires,said walls projecting radially inwardly of said land, and said blocksbeing comprised of a material more wear resistant than the material ofother portions of said die.

2. The apparatus of claim 1 comprising tapered grooves in said surfaceimmediately adjacent said blocks thereby increasing the flow of jacketmaterial over said drain wires. l

3. The apparatus of claim I wherein said die comprises three separableannular members said land being comprised in the first of said members,said recesses being comprised in the second of said members and saidthird members comprising a plurality of slots communicating with saidpassages for the admission of said wires into said jacket.

4. The apparatus of claim 3 comprising a tubular housing mounting saiddie, said housing comprising walls defining a plurality of slotscommunicating with said slots in said third member.

5. The apparatus of claim 1 wherein said recesses comprise wallscomprising first lengthwise grooves, said blocks comprise secondlengthwise grooves cooperating with said first grooves to define bores,and said apparatus comprises locking pins fitting said bores, therebyfixing the positions of said blocks.

1. Apparatus for extruding a cable jacket with embedded drain wirescomprising a die comprising: A. a tapered, interior surface, B. acylindrical land communicating with said surface, C. a plurality ofradial recesses opening on said surface, and D. a like plurality ofremovable guide blocks fitting into said recesses, said blockscomprising walls defining passages for said wires, said walls projectingradially inwardly of said land, and said blocks being comprised of amaterial more wear resistant than the material of other portions of saiddie.
 2. The apparatus of claim 1 comprising tapered grooves in saidsurface immediately adjacent said blocks thereby increasing the flow ofjacket material over said drain wires.
 3. The apparatus of claim 1wherein said die comprises three separable annular members said landbeing comprised in the first of said members, said recesses beingcomprised in the second of said members and said third memberscomprising a plurality of slots communicating with said passages for theadmission of said wires into said jacket.
 4. The apparatus of claim 3comprising a tubular housing mounting said die, said housing comprisingwalls defining a plurality of slots communicating with said slots insaid third member.
 5. The apparatus of claim 1 wherein said recessescomprise walls comprising first lengthwise grooves, said blocks comprisesecond lengthwise grooves cooperating with said first grooves to definebores, and said apparatus comprises locking pins fitting said bores,thereby fixing the positions of said blocks.